I'm going to have another try. This time I have chosen 5 species which be the ones which would be the most interesting to study.
Hallucigenia sparsa the strange fossil from the Burgess shale, which has been interpreted in several ways. Simon Conway Morris named it very appropriately as it is so strange. It may be an ancestor of the velvet worms. See
Hallucigenia - Fossil Gallery - The Burgess Shale I wonder how much the real animal would resemble the reconstructions.
Tiktaalik roseae, the fossil fish from Greenland that Neil Shubin thinks was close to the ancestral tetrapod, as it could probably 'walk' out of the water. We would find out if we could study a live one. The anatomy of its soft parts would be very interesting too, as the fossils can't give much information about them. See
Tiktaalik roseae: Home
An obvious choice is
Archaeopteryx lithographica. How well could it fly? Did it climb up trees and fly down? Or did it run along level ground and use its wings to hop, skip and jump into the air? I'd also love to know what colour its feathers were.
It would be nice to compare old
Archaeopteryx with a pterosaur. I thought first of
Pteranodon or
Quetzalcoatlus - but something smaller would be easier to manage and it would be nice to put one in a wind tunnel. I would choose
Pterodactylus antiquus with a 1 metre wingspan. It was roughly contemporary with
Archaeopteryx, but may have flown much better. See
https://en.wikipedia.org/wiki/Pterodactylus
Finally I would have to pick an ornithschian dinosaur, I think
Stegosaurus stenops would be good.
Archaeopteryx is effectively a saurischian dinosaur, so the comparison would be interesting. Of less importance, but still interesting would be the real arrangement of the bony plates on its back and their real function - there have been a lot of hypotheses, without very much evidence.
Alan